JSFiddle - React, Tailwind, and code Playground
HTML
<div ></div>
JavaScript
var sourceObj = {
propterty:"change Me",
anArray:[
{name:"first"},
{name:"second"}
]},
configJSON = '{"propterty":"New Val","anArray":[{"name":"third"}]}',
x = JSON.parse(configJSON);
// before
$("div").append(JSON.stringify(sourceObj))
$.extend(true,sourceObj,x);
//after
$("div").append("<br>"+JSON.stringify(sourceObj))